how do you know it's 7%? any way to check this? 1.5~7% is a huge difference.
you can simply monitor the hasrate on the pool side, a graph is usually presented. something like this
those ugly green arrows point to time periods that the dev fees were taking place. while this is not 100% accurate because a few other things aside form dev fees can show the same results ,but overall this is a highly accurate method to determine dev fees with little to no efforts.
take 24 hours of mining , sum the total "flat" time periods and get the percentage by doing a simple calculation.
do this for the first 24 hours if fees are higher than what you willing to pay > ditch it
if fees are fine , make a longer duration based test. maybe 72 hours. some devs are
the kernel log can also show you the results, but using the graph of your pool is usually the easiest way.
paying 7% for dev fees can be very stupid. simply because
assuming you went from 14 to 17th , then that's about 20% more hashrate, impressive right? but take a look at the power cost , it has increased, and you are paying 7% of your net-profit before paying for power. so at the end you might end up making just the same profit but risking your miner to failure by pushing it to it's limits.